Computing systems can exchange information via a data network by transmitting and receiving data packets according to one or more communication protocols. Network devices propagate the data packets through the network according to each device's configuration settings, network discovery and routing protocols, and flow control embedded in data communication protocols (e.g., SIP or a TCP handshake). Generally, data packets containing control information form a “control plane,” and data packets containing message content form a “data plane.”
A software-defined network (“SDN”) is a set of network devices in a data network that includes at least one network device that relies on a separate controller for configuration information such as updates to tables for routing network traffic. In some SDN implementations, an SDN controller is separated from a controlled network device by a network path reserved for control messages. This reserved control channel may also be referred to as the control plane. The SDN architecture separates network control from data packet forwarding. An SDN application may operate to manage network policies, regulate traffic patterns or resource usage, provide security, control a network protocol, provide quality of service commitments, or any other network task.